Lubricant composition comprising a mixture of waxy mineral oil, poly-1, 2-oxy-propyleneglycol and a phthalyl chloride acylated tetraparaffin-alkylated phenol



Patented Oct. 12, 1954 UNITED STATES PATENT OFFICE George J. Benoit,312, San Anselmo, Califi, as-

signor to California Research Corporation, San

being substantially without effect.

Francisco, Calif., a corporation of Delaware 3 Claims. 1

The present invention relates to the preparation of improved lubricatingoil compositions. More particularly, the invention has to do with thepreparation of lubricating oil compositions based on polyoxyalkylenepolymeric material and mineral oil, said compositions having improvedflow or pour characteristics.

The effect of pour point depressants on paraffinic mineral oils is wellknown. Good commercial depressants in amounts of 1 or less serve tolower the ASTM pour point appreciably. However, if the oil containingthe pour depressant is subjected to alternate chilling and thawing, thepour point at the end of each cycle rises until a constant value isreached, which is in general only slightly below the pour point of theoil containing no depressant. This phenomenon is known as pour pointreversion, and the final pour point, as the stable pour point.

Mixtures of mineral oil and polyoxyalkylene polymeric material, such asthat derived from 1,2-propylene oxide, have heretofore been proposed assuperior lubricant compositions. These mixtures have a particularutility in connection with the lubrication of moving parts, e. g., of aninternal combustion engine, operating at low ambient temperatures. t isobviously desirable, therefore, that in such an application the pourpoint of the mixture be quite low, for example, 20 F. and lower in thecase of a W/ oil.

Now, I have found that the incorporation into blends of paraffinicmineral oil and polyoxyalkylene polymeric material of a small amount ofa pour depressant of a specific type, hereinafter to be more fullydescribed, results in compositions having an unexpected lowered stablepour. More specifically, the pour point depressant contemplated by thepresent invention is of the Santopour type, that is, of a type derivedfrom a hydroxyaromatic compound as hereinafter to be more fullydescribed, and being solu'ble in the blend of mineral oil and polymericmaterial. I have found that the results sought are limited to theforegoing type of depressant, other conventional type depressants, suchas Para-flow (condensation product of paraffin 'wax and naphthalene),and Acryloid (polymers of acrylic and/or methacrylic acid esters),Likewise I have found that these results are peculiar to blends ofmineral oil and polyalkylene glycol polymeric materials.

More particularly, the pour point depressing materials I have referenceto are:

l. The parafiin-alkylated hydroxyaromatic 2 compound, such astetra-alkylated phenol of U. S. Patent No. 2,191,499;

2. The ester derivative of the above compound obtained by treating itwith an acylating agent, such as the phthalyl ester of tetra-wax phenol,and further described in U. S. Patent No. 2,138,809;

3. The product obtained as a result of the condensation reaction betweena resinified hydroxyaromatic compound and chlorinated wax (U. S. PatentNo. 2,061,008); or the resinified product of a hydroxyaromatic compoundcondensed with chlorinated wax (U. S. Patent No. 2,062,676). If desiredthese resinified products may be acylated.

According to the above-mentioned patents, hereby incorporated byreference, the hydroxyaromatic compounds that may be used are phenol,naphthol, and other hydroxy condensed ring compounds such as anthrol,together with derivatives of these hydroxy-substituted ring compounds.The following general formulas represent the compounds:

wherein R is a radical chosen from a group consisting of hydrogen,hydroxy, alkyl, aryl, alkaryl, alkoxy, and aroxy radicals. Preferablythose compounds in which R is hydrogen or a hydroxyl group and which arerepresented by the single ring Formula 1 are preferred. Accordingly, thepreferred specific compound is phenol. As examples of other specificcompounds which may be mentioned, are catechol, rosorcinol, B-naphthol,benzyl .phenol, p-cresol, hydroquinone,

3 xylenol, phenyl ethyl phenol, methyl hydroxydiphenyl, ethylhydroxydiphenyl, guaiacol, the monoethyl ether of catechol, methylnaphthcl, tolyl naphthol, xylyl naphthol, bcnzyl naphthcl,methoxyhydroxy naphthalene, anthranol, phenyl methyl anthranol,phenanthrol and the like.

The high molecular weight aliphatic compounds which have been founduseful in practicing the present invention are those that characterizecertain high molecular weight aliphatic hydrocarbons. These compoundsusually consist of more than 20 carbon atoms in the molecule and havemolecular weights of more than 250. This invention is concerned with thechlorine derivatives of compounds such as ceresin, ozocerite, paraffinwax, heavy parafiin oils, petrolatum, and similar hydrocarbons of a waxynature. Particularly useful is crystalline parafiin of a melting pointgreater than 120 F. and of about 130 F.

Preparation of the parayfin-alkylated hydroryaromatic compounds Theparafiin-alkylated hydroxyaromatic compounds are prepared by means ofthe Friedel- Crafts reaction involving the hydroxyaromatic compound andchlorinated hydrocarbon. In order to prepare the alkyl halide for theFriedel- Crafts synthesis, the aliphatic compound is first chlorinatedby any suitable means. rinated compound, for example, may be obtained bymelting paraffin wax of a melting point of about 130 F., heating themolten wax to an elevated temperature of about 200 F., then bubblinggaseous chlorine through the liquid mass together and then heated to atemperature of about 150 F., after which about 3% of an hydrous aluminumchloride, based on the chlorparafiin, is added a little at a time andwith constant agitation to the molten mixture and then the reactionmixture is slowly heated to a temperature of about 350 F., a heatingtime of about two hours being satisfactory. If evolution of gas has notceased by the time a temperature of 350 F. is reached, the mixture isheld at this temperature until all evolution of gas has ceased. Usuallyat this stage of the reaction an aluminum chloride sludge will begin tosettle quite rapidly to the bottom of the reaction vessel and atranslucent solution layer appears above the sludge. After completion ofthe reaction the paraffin-alkylated hydroxyaromatic compound is purifiedin any suitable manner, as for example, by drawing on the liquid layer,then washing several times with warm water to rid it of any residualhydrochloric acid, and then distilling.

Preparation of the ester of a. parafitn-alkylated hydrozryaromaticcompound As hereinbefore mentioned, ester derivatives of thepara-flin-alkyla'ted hydroxyaromatic oom- The chlopounds are suitablepour point depressants. As esterifying or acylating agents a wide numberof acid chlorides or anhydrides are suitable. The following are suitableorganic acylating agents: the monobasic saturated aliphatic acids fromacetic acid up to and including montanic acid; monobasic unsaturatedaliphatic acids, such as acrylic; aliphatic saturated and unsaturatedpolybasic acids, such as oxalic and fumaric acid, respectively;substituted aliphatic mono and polybasic acids, the substituent groupsbeing halogen, amino, or hydroxyl groups; aromatic mono and polybasicacids such as benzoic and phthalic, respectively; alkene-substitutedaromatic monobasic acids such as cinnamic; substituted mono andpolybasic aromatic acids, such as chlorobenzoic, salicylic, toluic,etc., aryl-substituted mono and polybasic aliphatic acids with thecarboxyl group occurring in the aliphatic portion of the molecule;heterocyclic acids, such as furoic; alicyclic acids, such as abietic.

In general, I prefer a dibasic acid, such as phthalic, as theesterifying acid.

In the acylating operation, the acid halide or anhydride is added afterthe Friedel-Crafts reaction is completed, that is, when all evolution ofgas at a temperature of around 350 F. has ceased. The mixture is thencooled to a point below 350 F. but above 100 F. The esterificationreaction proceeds rapidly and is complete upon cessation of allevolution of gas. The esterified paraffin-alkylated product may then bepurified in a similar manner in which the intermediate product, theparaffin-alkylated hydroxyaromatic compound, is isolated, that is, bydrawing off the liquid layer, washing this layer extensively with waterand subsequently distilling.

Preparation of the condensation product between a resz'm'fiedhydroxyaromatic compound and chlorinated paraflin In the preparation ofthe resinified hydroxyaromatic compound prior to condensing it with thechlorinated paraffin by means of the Friedel- Crafts reaction, suitableresinifying agents are halogenated organic compounds, halogenatedaralkyl or aryl hydrocarbons, as for example, benzyl chloride andchloronaphthalene; aldehydes, which eliminate Water in the reaction withthe hydroxyaromatio compound, such as formaldehyde; alcohols, ketones,and polyhydric compounds such as butyl alcohol, acetone and glycol,which also eliminate water in the reaction; elemental sulfur and sulfurcompounds, such as sulfur monochloride, with the elimination of hydrogensulfide. In general, preference is for the aldehyde type of resinifyingagent.

The reaction between an aldehyde and a hydroxyaromatic compound readilyoccurs in an acid or basic medium. For example, the reaction betweenbutyraldehyde and phenol readily takes place at a temperature of about212 F. in the presence of about 1 per cent hydrochloric acid catalyst,the proportion of the reactants being mole of the aldehyde to 1 mole ofphenol. After completion of the resinification reaction, the resin maybe purified by subjecting it to a vacuum distillation to removeunreacted products.

In preparing the hydroxyaromatic-sulfur resin either elemental sulfur ora compound thereof, such as sulfur monochloride is suitable. Thereaction between sulfur monochloride and the hydroxyaromatic compoundoccurs readily, and no catalyst is necessary. Since the solubility ofthesulfur resin depends-on the-degree of combined sulfur, that is, thegreater the sulfur content the less the solubility, the most suitablehydroxyaromatic-sulfur resin is one that has not more than one atomicweight of sulfur combined with each mole of hydroxyaromatic compound.

While the foregoing describes the preparation of the resin by reacting ahydroxyaromatic compound with a suitable resinifying agent, I-may alsoprepare the resin through the reaction of an oxyaromatic compound with asuitable resinifying agent. As examples of suitable oxyaromaticcompounds may be mentioned the arcmatic ethers, such as anisole (phenylmethyl ether) and beta-naphthyl methyl ether. A suitable resinifyingagent is an aldehyde, such as formaldehyde. The resinification reactionbetween an aromatic ether and the aldehyde proceeds less readily than isthe case with the hydroxyaromatic compounds. The reaction between anoxyaromatic compound and an aldehyde, such as formaldehyde, may beaccelerated by employing a higher concentration of an acid catalyst,concentrated sulfuric acid being preferred. Often it is desirable to usea solvent for the mixture. A suitable solvent is glacial acetic acid.

In preparing the oxyaromatic-aldehyde resin, anisole, acetic acid, andtrioxymethylene are mixed together. For every mole of anisole, 10.8 g.of trioxymethylene, and 1 mole of glacial acetic acid are employed. Tothis mixture about 43 cc. of concentrated sulfuric acid are added slowlywith cooling, so that the reaction temperature is maintained below 50 C.After the addition of all the sulfuric acid, the mixture is stirred forabout 2 hours at 50 C. The resin is then purified by washing with Water,dissolving in a suitable solvent such as benzene, washing with alkali torid the product of all acid, distilling off the solvent, and furtherpurifying by vacuum distillation.

The condensation reaction between the resin and the chlorinated paraffinis carried out in about the same manner as is employed in condensing theunresinified hydroxyaromatic compound with the chlorparafiin, that is,the chlorparafiin is melted, the resinified hydroxyaromatic compound oroxyaromatic compound is mixed therewith, aluminum chloride is added, andthe mixture heated to a maximum of 350 F. If difficulty is encounteredin mixing the resin with the paraffin, a solution of resin in a suitablesolvent, such as ethylene dichloride, may be advantageously employed. Inthis case, the addition of aluminum chloride takes place at the boilingtemperature of the solvent, after which the solvent is distilled ofi andthe elevated temperature of 350 F. is reached. When the reaction betweenthe resin and chlorparafiin is completed, usually after one hour, thefinal product is isolated in the usual manner of purifyingFriedel-Crafts reaction products. The liquid layer is decanted,dissolved in any suitable solvent such as ether to aid in the subsequentwashing operations; the solvent is then distilled off, and the compoundfurther purified by distillation, such as by vacuum distillation at 5mm. and at a temperature of about 350 C.

In general, the class of resinifying agents employed in theresinification of the unsubstituted oxyaromatic compound are suitablefor the resinification of the compound after alkylation, although theintroduction of alkyl groups into the oxyaromatic compound makes thecompound less reactive to these agents.

Polyoxyallcylene polymeric material The preferred polyoxyalkylenepolymeric material contemplated by the invention has the structuralconfiguration L llJ.

This material is prepared from the alkylene oxides, such as ethyleneoxide, 1,2-propylene oxide, the butylene oxides and higher homologs,mixtures thereof, and the corresponding alkylene glycols. The resultingproducts may be polyoxyalkylene diols or polyalkylene glycolderivatives, in which one or both of the terminal hydroxyl groups havebeen removed either during the polymerization reaction or subsequentlythereto, as by etherification or esterification, to yield monoordi-ether or monoor di-ester groups, or combinations of such terminalgroups, whereby certain desirable properties are imparted to the finalpolymeric mixture.

For example, U. S. Patent No. 2,448,664 describes the preparation ofpolyoxypropylene polymeric mixtures of lubricating oil viscosity rangingin molecular weight from around 500 to 2,000 and higher. The reactionmay be represented as follows:

ROH (OCzHa-CHs R-(OCzHrCHsMOH Monohydric 1,2-propylene alcoholPolyoxypropylcnc monooxide hydroxy compound The preparation ofcopolymeric polyalkylene oxide mixtures from ethylene oxide andpropylene oxide are described in U. S. Patent Nos. 2,425,755 and2,425,845. U. S. Patent No. 2,457,139 describes esters ofpolyoxyalkylene diols derived from a copolymer of ethylene oxide and1,2-propylene oxide, while U. S. Patent No. 2,480,185 describes estersof polyoxyalkylene monohydroxy compounds derived from the samecopolymer. Diethers of polyoxyalkylene diols derived from ethylene oxideand propylene oxide are described in U. S. Patent No. 2,520,611, and U.S. Patent No. 2,520,612 describes diethers of polyoxypropylene diols.Preferably employed in accordance with the invention is the diether ofpolyalkylene glycol or the monoether monoester of polyalkylene glycol,derived most advantageously from 1,2- propylene oxide.

Also contemplated by the invention are polyoxyalkylene polymeric andcopolymeric mixtures containing polymer units having more than twocarbon atoms separating oxygen atoms in the polymer chain. For example,U. S. Patent No. 2,525,733 describes polymers and copolymers preparedfrom trimethylene glycol.

The polymeric materials hereinabove described, as well as additionalsuitable polymeric materials of the character indicated are described inU. S. Patent No. 2,491,432.

Blend of mineral oil and polymer In forming the blend of polyalkyleneglycol polymer material and mineral oil, any waxy mineral or hydrocarbonoil of lubricating oil viscosity can be employed. It can be an unrefinedmineral oil or a distillate derived from paraiiinic or mixed basecrudes. Moreover, the oil may be an oil refined by conventional methods,such as solventor acid-treated hydrocarbon oils or mixtures thereof. Ifdesired, synthetic hydrocarbon oils derived from the polymerization ofolefins or the Fischer-Tropsch process can be employed. Various blendedoils are also contemplated by the invention.

As hereinbefore stated, the compositions of the invention are especiallyuseful for low temperature operation of internal combustion engines, andcompositions satisfying the requirements of a 10 W/20 oil areparticularly useful. Accordingly the preferred polymeric material rangesin molecular weight from about 400 to about 950, most advantageously,from about 50 to about 700; and has a viscosity of about 35 to 60 SSU at210 F., most advantageously between about 40 and 50 SSU at 210 F. Theviscosity of the mineral oil on the other hand will depend on theviscosity of the polymer, the viscosity desired in the final blend, andthe mineral oil content of the blend. In general, the viscosity of themineral oil at 210 F. is in the range of about 35 SSU to about 100 SSU,preferably 50 to 70. The viscosity of the mineral oil at lowertemperatures, e. g., 100 F. can vary over a wide range, depending on theviscosity of the mineral oil at 210 F., the viscosity index of themineral oil (ranging from about 30 to 110, preferably 50 to 10 and thefraction of mineral oil in the blend. Additional description ofpreferred mineral oil and polymer appears in the copending applicationof William T. Stewart and George J Benoit, J r., filed August '7, 1950,and bearing Serial No. 178,165, now abamcloned.

Blends of hydrocarbon oil and polymer contemplated by the presentinvention contain 25 to '75 volume per cent of either one of thecomponents, and the remainder, the other component; that is, either ofthe components may be present in an amount of one-third to threefold theamount of the other. The preferred blend, however, contains an amountabout equal by volume of mineral oil and polymer, that is, about 50volume per cent of each component.

Effective amounts of pour point depressing material ranges from about0.5% to by weight of the finished composition. Moreover, the hereindescribed pour point depressing substance has been found to be effectivein compositions containing certain additives employed to modify theproperties of the composition. Among these additives may be mentioneddetergents, such as alkaline earth phenates; corrosion and oxidationinhibitors, such as certain aromatic amines, metal dithio carbonates;viscosity index improvers; deioaming agents; metal deactivators, etc.

The following example is illustrative of the invention:

(a) Paraflln base 480 neutral mineral oil having a viscosity index of85, an ASTM pour point of about 5 F., and a stable pour point of about 5F., was treated with about 3% of a phthalyl chloride acylatedtetraparaifin-alkylated phenol. The stable pour point of the resultingmixture was F.

(b) A mixture was formed employing 60 volume per cent of the oildescribed in (a) and 40 volume per cent of 1,2-polypropylene glycolmonoisooctyl ether acetate having a molecular weight of about 500. Thestable pour point of this mixture was about 5 F.

(c) Incorporation in the mixture of (b) of about 3% of the phthalylchloride acylated tetraparaffin-alkylated phenol mentioned in (a), andhereinafter more fully defined, resulted in a mixture having a stablepour point of 25 F.

(cl) Addition of 3% Acryloid and 3% "Parafiow to separate samples ofmixture (b) lowered the stable pour to only 0 F. and 10 F.,respectively.

The stable pour points mentioned in the foregoing example weredetermined according to Federal Specification Mil-O-Zlil l (0RD),paragraph 4.3.3. The acylated tetraparafiin-alkylated phenol wasprepared by means of the Friedel-Crafts synthesis employing 1,000 g.chlorinated paraffin wax, 92.5 g. phenol, 100 g. of the isolatedalkylated phenol then being treated with about 10 g. phthalyl chloridefor about 15 minutes at a temperature between about 175 F. to 250 F. togive the high molecular weight alkyl phenyl phthalate.

Another example of the invention is as follows:

(a) About parts by volume of the parafiin base e neutral mineral oilemployed above and 25 parts 185 parafiin base bright stock having anASTM pour of 10 F. and a V. I. of were blended. The blend had a stablepour of 10 F.

(b) The mixture or" (a) was mixed, in equal volumes, with polypropyleneglycol butyl methyl diether having a molecular weight of about 500. Thestable pour of this mixture was 10 F.

(0) Addition of 2% to the mixture of (b) of the phathalyl chlorideacylated tetraparaffinalkylated phenol employed in the foregoingexample, lowered the stable pour of the mixture to 20 F.

(d) To separate samples of the mixture of (b) there were added 2%Acryloicl and 2% Parafiow. The stable pours were 0 F. and -5 F.,respectively. The stable pour point in this example was determined asabove indicated.

Obviously many modifications and variations of the inventionhereinbefore set forth may be made Without departing from the spirit andscope thereof, and, therefore, only such limitations should be imposedas are indicated in the appended claims.

I claim:

1. A lubricant composition comprising a mixture of a. waxy mineral oiland a poly-1,2-oxypropylene glycol in the proportion of from 25 to 75%by volume of the mineral oil and from 75 to 25% by volume of the glycol,together with from about 2% to about 3%, by Weight, of a phthalylchloride acylated tetraparaffin-alkylated phenol.

2. The composition of claim 1 wherein the poly- 1,2-oxypropy1ene glycolmaterial is the monoisooctyl ether of poly-1,2-oxypropylene glycolacetate.

3. The composition of claim 1 wherein the poly- 1,2-oxypropylene glycolmaterial is the butyl methyl diether of poly-1,2-oxypropy1ene glycol.

References Cited in the file of this patent pages 98-100 pertinent.(Copy in Scientific Library.)

1. A LUBRICANT COMPOSITION COMPRISING A MIXTURE OF A WAXY MINERAL OILAND A POLY-1,2-OXYPROPYLENE GLYCOL IN THE PROPORTION OF FROM 25 TO 75%BY VOLUME OF THE MINERAL OIL AND FROM 75 TO 25% BY VOLUME OF THE GLYCOL,TOGETHER WITH FROM ABOUT 2% TO ABOUT 3%, BY WEIGHT, OF A PHTHALYLCHLORIDE ACYLATED TETRAPARAFFIN-ALKYLATED PHENOL.